In the conventional technology, a method of preparing copolymer of 1-alkene and vinyl monomer using a metallic complex compound catalyst has been known. Due to high affinity of a metal to oxygen, however, the method has a disadvantage that the metallic complex compound catalyst based on transition metal and lanthanide-based metal in the first development stage is easily contaminated by a functional group (C═O) of a polar vinyl monomer. Although it has been reported that the copolymer of alkyl acrylate and 1-alkene may be prepared using a metallic complex compound catalyst based on some of transition metal in the later development stage, the copolymer still has a large amount of 1-alkene.
The 1-alkene-based copolymer prepared by using the metallic complex compound catalyst includes only a small amount of a polar group so that polyolefin crystals remain in the copolymer, which is not desired for optical products, such as a transparent film.
On the other hand, in order to overcome the disadvantage of the polymerization method by the metallic complex compound catalyst, that the metallic complex compound catalyst is contaminated by oxygen existing in a polar group and the activity of the metallic complex compound catalyst thus decreases and that a polymer having a small amount of a polar group contained therein is obtained, a controlled radical polymerization has been proposed. When the copolymer of 1-alkene and polar vinyl monomer is produced by ATRP (Atom Transfer Radical Polymerization) method, which is a representative polymerization method among the controlled radical polymerization methods, the amount of the polar vinyl monomer is larger than that of 1-alkene, contrary to the polymerization method by the metallic complex compound catalyst. That is, a random copolymer in which the amount of 1-alkene is controlled in some degrees according to the conditions of copolymerization may be produced. However, when the copolymer is produced by ATRP method, it takes long time to obtain high molecular weight and the copolymer having the so small amount of 1-alkene is obtained.
In addition, the 1-alkene-alkyl(meth)acrylate copolymer produced by the ATRP method has the small amount of ethylene in the polymer chain so that the copolymer can be easily broken and thus film properties decrease.
Since 1-alkene-acrylate-based copolymer has high transparence and adhesiveness, the polymer may be used for optical products. To do this, its thermal resistance should be excellent so that there is no deformation occurred by heat created when process of preparation and optical instruments are operating. Accordingly, there is a need to develop terpolymers including further a new monomer which can improve properties such as the thermal resistance.